Naturally occurring substances from algae are known to inhibit the development of mosquito larvae into the adult stage. These substances show signs of acting selectively. The primary objectives of the research are to isolate and identify such mosquito larvicides produced by the fresh water green alga Cladophora and thereafter develop them as mosquito control agents. Various forms of chromatography will be employed as separation procedures. The separation will be monitored by the composite sample bioassay using A. aegypti as the test organism. Spectral techniques will be utilized for identification. Evaluation of the control effectiveness will be carried out in the laboratory and in the field.